So far, an LED lamp widely used in places such as a parking lot or a stairway generally has an integrative structure, which causes inconvenient in installation and maintenance. For example, a special LED lamp used in a parking lot is disclosed in Chinese utility model patent 201120104517.7. Because the LED lamp is integrated, heavy and large, it has difficulties in holding and locating when the LED lamp is mounted on a ceiling or a wall, and the LED lamp has to be removed entirely when the LED lamp fails to work, which is very inconvenient.